This ability is important because surface tension, (one of the physical properties that determines how liquids behave) must be overcome for the two liquids to effectively intermingle. Emulsions are formed by mixing these two liquids with a third substance, known as an emulsifier, which creates a uniform, stable dispersion of the first liquid in the second.Įmulsifiers belong to the class of chemicals known as surfactants, or surface active agents, which are able to reduce the surface tension of liquids. Emulsions are created by surfactantsĪn emulsion can be described as a collection of tiny droplets of one liquid (e.g., an oil) dispersed in another liquid (e.g., water) in which it, the first liquid, is insoluble. Today, many products including drugs, paints and inks, cosmetics, and even certain foods, are made possible through the use of emulsions. In recent times, emulsions have been developed to deliver medicine in the form of ointments. Early societies learned to take advantage of this natural phenomenon for example, the ancient Egyptians used eggs, berry extracts, and oils to form crude emulsified paints. Emulsions throughout historyĮmulsions in one form or another, have been used for centuries. These properties make emulsions useful in a variety of products including pharmaceuticals, cosmetics, paints and inks, pesticides, and foods. The word emulsion is from the seventeenth century Latin words emulgere and emulsum, which means to milk.Įmulsions provide a variety of benefits such as the ability to deliver water insoluble active materials from water based products, to improve control over a prod-uct ’s physical properties, and effectively dilute expensive or hazardous functional materials. They continue to find application in a variety of industries. A detergent is a common surfactant.) Humans have used emulsions for centuries. (A surfactant is any soluble substance that reduces the surface tension between two liquids, or one solid and one liquid. It is an unstable system, which can be made more stable by the presence of a surfactant. An emulsion is a two-phase system that has at least one immiscible liquid (one incapable of being and remaining mixed), called the dispersed phase, distributed in another liquid or solid, called the dispersion medium, in the form of tiny droplets.

Liquid emulsion meaning